Twelve Days of Christmas #2: Was Jesus born in 1 AD?

Around Christmastime, we often encounter the assumption that Jesus was born in 1 AD (AD representing the phrase anno Domini, meaning “in the year of the Lord”). Our modern calendars are based on this assumption thanks to a monk named Dionysius Exiguus (c. 470–544). The exact date isn’t quite so clear, because we’re working with ancient documents whose authors had very little interest in giving precise dates for important events. (Also, contrary to what some people might think, there is no “Year Zero.”)

Most scholars place the birth of Christ around 6-4 BC. They arrive at this date by calculating as much as two years (Matthew 2:16-18) backward from the death of Herod the Great (c. 4 BC). However, this date has a few problems as well, primarily involving an alleged historical inaccuracy in the Bible. Luke mentions that John began baptizing people in the fifteenth year of the reign of Tiberius Caesar (Luke 3:1-2), which would have been approximately AD 28-29. He also mentions that Jesus was about thirty when he began his ministry (Luke 3:23). If we subtract thirty years, we arrive at a date of 1-2 BC. That puts the birth of Christ after the death of Herod, which creates a contradiction with both Matthew’s and Luke’s chronology.

Several important factors come into play here. One involved the date of Herod’s death, usually dated to 4 BC. This is based on a reference to a lunar eclipse in the writings of Josephus (Antiquities 17.6.4). A minority of scholars have dated Herod’s death to 1 BC, arguing that the lunar eclipse in 4 BC was rather unspectacular, and there was a much more memorable one that occurred in 1 BC (two, in fact). Neither option is free of problems.

A second consideration is that Luke does not say that Jesus was exactly thirty years old. He says that he was “about” thirty (Luke 3:23). This was the age when a man became eligible to serve as a priest in Israel, which leads some to conclude that this is supporting evidence for the belief that Jesus was precisely that age when he began his ministry. The text does not demand this, however, and men in ancient Israel could serve as a priest anywhere between the ages of thirty and fifty (Numbers 4:3).

Virtually everyone recognizes that Jesus was not born in 1 AD. The actual year of his birth remains uncertain, but we have some good guesses. The majority opinion is that it could have been in 4-6 BC, but a solid case can be made for 2-3 BC also if we’re willing to do a little detective work:

Luke states that John began to baptize in the fifteenth year of Tiberius (AD 28-29; cf. Luke 3:1-2).

Jesus begins his ministry around the age of thirty (Luke 3:23)—roughly the same time John begins baptizing.

Working backward, we arrive at a date of 1-2 BC for the birth of Jesus.

Herod died during a lunar eclipse, which we know occurred in 1 BC.

Herod ordered the deaths of infants aged two years and younger (Matthew 2:16-18).

Considering all the evidence, there is a possibility that the date for Jesus’ birth was c. 2-3 BC. The timeline is pretty tight, and it also calls into question the work of Josephus, which is used as the basis for establishing the date of Herod’s death. However, it would be difficult to imagine that Luke—who is often extremely careful in reporting fine details—would make such a monumental historical blunder by putting the birth of Christ during Herod’s reign if it were not so.